many of the major malaria vectors found in the malaria endemic countries in this ICEMR. In addition, recent data has shown that additional minor vectors are found, including members of the Longirostris and Bancroftii groups resulting in remarkable vector species richness, ranging from 16 species in Papua New Guinea to 4 in the Solomon Islands but only 1 in Vanuatu (An. faruati No 1). Unlike the primary vectors of malaria in Africa, the vectors found in these Pacific island ountries are predominantly zoophilic, exophilic and exophagic. It is these exophilic vectors which may pose the greatest threat to malaria elimination efforts as they are not only impacted less by LLINs and IRS (that require house entering to be effective), but they have previously demonstrated behavioral plasticity during the elimination efforts in the 1960s-70s by blood feeding both earlier and outside of houses thereby avoiding contact with DDT sprayed walls. To understand malaria transmission and to react rapidly to threats to the effectiveness of vector control strategies requires: (1) being able to identify isomorphic anophelines, (2) being able to incriminate malaria vectors, (3) knowing the behaviors of the vectors before interventions, (4) understanding how changes in vector behaviors change in response to the interventions to mitigate their effectiveness and (5) understanding how the underlying genes responsible for behavioral changes move through populations.Significance and gaps exist in our present knowledge of each of the above factors. In order to rationally guide malaria control interventions directed against the malaria vectors, the relationships among the vector, parasites and host needs to be understood in more detail. This project will therefore undertake a coordinated set of in-depth entomological studies combining continuous surveillance of the vectors and their behaviors with state-of-the-art molecular identification of vector species and Plasmodium infections in vectors. The gaps in knowledge to be addressed are: i) to define the malaria vector status of anophelines and to characterize the behavioral attributes that determine their relative contributions to transmission;ii)To determine vector complexity and its relationship to transmission intensity;iii)To assess the dynamics between vector behaviors and the efficacy of vector control interventions, i.e. the resilience ofthe vectors to control measures;iv) To understand the relationship between parasite species and strains and vector species and strains. Project 2 will fill these critical gaps in our knowledge needed to guide the effective application of malaria vector control strategies. RELEVANCE (See instructions): Malaria in Papua New Guinea and the Solomon Islands, with the highest rates outside of sub-Saharan Africa, is transmitted by complexes of isomorphic species that exhibit exophilic, exophagic and zoophilic behaviors making indoor residual spraying and long lasting insecticide treated nets less effective than in areas with endophilic vectors. Effective control and elimination of malaria may not be feasible unless we understand the vectors'behaviors and how the underlying genes responsible for behavioral changes move through populations. This project will link vector ecology and behavior to malaria control effectiveness